The use of stents in bodily lumen is well known. A stent is typically delivered in an unexpanded state to a desired location in a bodily lumen and then expanded.
The stent may be expanded via the use of mechanical device such as a balloon or the stent may be self-expanding.
Because a stent often must be delivered through tortuous anatomy, it is desirable for the stent to be flexible. It is also desirable for the stent to exhibit high scaffolding strength in the expanded state. In general, however, as stent flexibility is increased, scaffolding strength is decreased and similarly, as scaffolding strength is increased, flexibility is decreased.
There remains a need for a stent having a high degree of flexibility in the unexpanded state and high scaffolding strength in the expanded state.
All U.S. patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
The invention in various of its embodiment is summarized below. Additional details of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
In one embodiment, the invention is directed to a stent comprising a plurality of interconnected circumferential bands with a flowpath therethrough. At least one of the bands includes at least one substantially M-shaped segment selected from the group consisting of convex M-shaped segments and concave M-shaped segments. In the case of a convex M-shaped segment, the segment comprises a first convex outer leg, a second convex outer leg and a connector connecting the first convex outer leg and the second convex outer leg. In the case of a concave M-shaped segment, the segment comprises a first concave outer leg, a second concave outer leg and a connector connecting the first concave outer leg and the second concave outer leg.
Desirably, the at least one band comprises a plurality of M-shaped segments whether convex, concave or both. Where present, adjacent convex M-shaped segments may be interconnected via a loop extending therebetween. The loop may optionally comprise a concave first portion and a concave second portion. Where present, adjacent concave M-shaped segments may be interconnected via a loop extending therebetween. The loop may optionally comprise a convex first portion and a convex second portion. Where convex M-shaped segments are present in multiple bands, they may optionally be inverted relative to one another in adjacent bands. Similarly,where concave M-shaped segments are present in multiple bands, they may optionally be inverted relative to one another in adjacent; bands.
In another embodiment, the invention is directed to a stent comprising a plurality of connected bands. At least one of the bands comprises a repeating pattern of three or more substantially parallel interconnected segments with a first curvature and three or more substantially parallel interconnected segments with a second curvature. One of the segments with the first curvature is connected to one of the segments with the second curvature. Desirably, the first curvature is opposite to the second curvature. Also desirably, the stent comprises a plurality of the bands with each band comprising a repeating pattern of three or more substantially parallel interconnected segments with a first curvature and three or more substantially parallel interconnected segments with a second curvature, one of the segments of the first curvature connected to one of the segments with the second curvature.
In another embodiment, the invention is directed to a stent comprising a plurality of interconnected circumferential bands where at least one of the bands has a proximal end and a distal end and one of the proximal and distal ends comprises at least one first loop and at least one second loop. The first loop includes a portion which is disposed substantially circumferentially and the second loop includes a portion which is substantially arrow shaped. Desirably, at least one of the bands comprises a plurality of first and second loops alternating with one another. Also desirably, the stent comprises a plurality of such bands. Adjacent bands may be connected one to the other to form combined bands with openings therein.
The invention is also directed to a stent comprising at least one first cell having a first end and a second end. The first end terminates in a circumferential component and the second end terminates in an arrow-shaped component opposite the first end. The stent may comprise a plurality of such interconnected first cells. Desirably, the first cells are interconnected circumferentially about the stent and/or longitudinally along the length of the stent.
In another embodiment, the invention is directed to a stent comprising a plurality of serpentine bands extending in a longitudinal direction, including a first serpentine band and a second serpentine band. The first and second serpentine bands are connected by at least one loop member and desirably a plurality of loop members extending in a direction non-parallel to the longitudinal axis of the stent. All or some of the longitudinally adjacent first loop members may open toward the proximal end of the stent. Optionally, longitudinally adjacent first loop members may be oppositely oriented about the longitudinal axis of the stent.. The stent may comprise additional serpentine bands extending in a longitudinal direction and connected to adjacent serpentine bands via additional first loop members.
In another embodiment, the invention is directed to a stent comprising at least one first cell comprising a first generally longitudinal sidewall having at least one bend therein, a second generally longitudinal sidewall having at least one bend therein, wherein the first generally longitudinal sidewall is substantially parallel to the second generally longitudinal sidewall, a proximal wall having at least one loop therein, the loop oriented non-parallel to the longitudinal axis of the stent and a distal wall having at least one loop therein, the loop oriented non-parallel to the longitudinal axis of the stent. Desirably, the stent comprises a plurality of such cells arranged longitudinally and/or circumferentially about the stent. All of the loops in the proximal walls of the cells and all of the loops in the distal walls of the cells may be substantially parallel to one another or may be non-parallel to one another.
In another embodiment, the invention is directed to a stent comprising a plurality of bands, where each band comprises a plurality of distally directed loops and a plurality of proximally directed loops. Each distally directed loop has an open end and a closed end and each proximally directed loop has an open end and a closed end. The proximally directed loops and the distally directed loops are non-parallel to the longitudinal axis of the stent and alternate around the band. Optionally, the proximally directed loops and the distally directed loops may be parallel to one another. Circumferentially adjacent proximally directed loops and distally directed loops are connected to one another by first connectors which extend from the open end of the proximally directed loops to the open end of the distally directed loops. The first connectors include a circumferential component. Bands which are adjacent one another are connected by one or more second connectors extending therebetween. The second connectors desirably have at least one bend therein.
in another embodiment, the invention is directed to a stent defined by a structure comprising a plurality of serpentine portions. Each serpentine portion has at least one peak and one trough. At least some of the serpentine portions advance discontinuously in a helical path about a longitudinal axis of the stent to form a discontinuous helical band. The serpentine portions may also be arranged such that at least some of the serpentine portions advance discontinuously in a substantially longitudinal path about a longitudinal axis of the stent to form a discontinuous band extending substantially in a lengthwise direction. Desirably, each of the serpentine portions forming the discontinuous band consists of one peak and one trough where the peak and trough are disposed at a non-zero angle with respect to the longitudinal axis of the stent. Also desirably, the serpentine portions may be arranged to form a plurality of discontinuous helical bands or discontinuous bands extending substantially in a lengthwise direction. All of the serpentine portions may be connected so as to form a continuous path extending from one end of the stent to the other end of the stent.
In yet another embodiment, the invention is directed to a stent comprising a meandering path of connected serpentine portions, each serpentine portion comprising first and second loop portions which are arranged side-by-side and have a side in common. The first and second loop portions each open in a non-longitudinal direction. Adjacent serpentine portions along the meandering path are connected by a connector having a longitudinal component and a circumferential component. Furthermore, adjacent serpentine portions along the meandering path are displaced longitudinally and circumferentially from one another. The serpentine portions may be arranged in at least one discontinuous band extending in a substantially longitudinal direction or the discontinuous band may extend substantially helically about a longitudinal axis of the stent. Desirably, each serpentine portion consists of a first loop and a second loop.
The invention is also directed to a stent comprising a meandering, substantially helical path of connected serpentine portions where each serpentine portion comprises first and second loop portions which are arranged side-by-side and have a side in common. The first and second loop portions each open in a non-longitudinal direction. The serpentine portions may optionally be arranged in at least one discontinuous band extending in a substantially longitudinal direction or in at least one discontinuous band extending substantially helically about a longitudinal axis of the stent.
The invention is further directed to a stent comprising at least one and desirably a plurality of omega building blocks. The omega building block comprises a circumferentially oriented omega-shaped loop, a substantially proximally oriented first lobe extending from the proximal end of the omega-shaped loop and a substantially distally oriented first lobe extending from the distal end of the omega-shaped loop. Where a plurality of omega building blocks are present, the omega building blocks are desirably arranged in one or more bands extending in a lengthwise direction. Longitudinally adjacent omega building blocks in the band extending in a lengthwise direction are connected by dual lobe members. Each dual lobe member comprises a substantially proximally oriented second lobe and a substantially distally oriented second lobe connected to the substantially proximally oriented second lobe. The substantially proximally oriented second lobe is at the proximal end of the dual lobe member and the substantially distally oriented second lobe is at the distal end of the dual lobe member. The substantially distally oriented first lobe of an omega building block is arranged side by side and has a side in common with the substantially proximally oriented second lobe of a dual lobe member and the substantially proximally oriented first lobe of a longitudinally adjacent omega building block is arranged side by side and has a side in common with the substantially distally oriented second lobe of the dual lobe member. At least one and desirably a plurality and more desirably all of the omega shaped loops are connected circumferentially to circumferentially adjacent dual lobe members between the substantially proximally oriented second lobe and the substantially distally oriented second lobe.